Ok, I dont like to relay too much on "tech", but since this isnt a leisure trip, I've identified some useful things I tend to book:
- pupuru.com: wifi/lte router, slim 400Y/day removing the need to deal with foreign SIMs
- suica: to pay underground
- maps.me: loaded prefecture of tokyo and put in place my needed hotels/venue/stations

Unsure about a reading-kinja app.